1. Field
Embodiments described herein relate to information processing devices and method thereof, and more particularly, to processing which decrypt encrypted content using keys, key storage management devices which store and manage keys and provide keys upon requests made by information processing devices, and content processing systems having content processing devices and key storage management devices. An embodiment relates to a content processing program which is executed by a computer and causes the computer to operate as content processing devices.
2. Description of the Related Art
Services for deleting data in lost mobile phones have been developed in order to reduce the risk of unauthorized use by third parties and the risk of leakage of stored personal and company data. Such a service is described in the web page <http://www.kddi.com/business/pr/benri_pack/datasakujo.html>.
In this service, an address book, a mail box, data in application programs, data in an internal memory or in a memory connected to an expansion slot, and the like are to be deleted.
Examples of other techniques of deleting data and keys are discussed in the following documents.
Japanese Unexamined Patent Application Publication No. 2007-97023 discusses a technique in which various deletion conditions are set in a mobile terminal capable of wireless communication, and when the set conditions are satisfied, data is deleted under the control of the mobile terminal.
Japanese Unexamined Patent Application Publication No. 2005-341156 discusses a technique in which an encrypted content key is deleted when encrypted content is deleted.
Japanese Unexamined Patent Application Publication No. 2000-183867 discusses a technique for preventing leakage of an encryption key stored in a device in the event of theft which is used in a highly secured system using cryptography for preventing tampering. Japanese Unexamined Patent Application Publication No. 2000-183867 also discusses a technique in which a cryptographic key is stored in a volatile storage unit in a cryptographic processing device having a possibility of being stolen, and the cryptographic key is deleted when the device is turned off due to theft.
Japanese Unexamined Patent Application Publication No. 2004-355268 discusses a technique in which a plurality of split information pieces corresponding to split components of an encryption key or a decryption key are stored in different storage areas. In this technique, the encryption key or the decryption key may be deleted when operation of an information processing device is stopped due to power being cut-off and when the device becomes incapable of information processing. The encryption key or the decryption key may also be deleted when encryption or decryption of information is completed.